Overview of Topic and Indo-U.S. Collaboration. This is a proposal for an R21 to develop and pilot test a behavioral HIV prevention intervention for men who have sex with men (MSM) in Chennai, India. It is the next natural step in an ongoing Indo-U.S. collaborative program of research between investigators in Boston (MGH/Harvard and Fenway Community Health) and in Chennai, India (ICMR, Tuberculosis Research Center, Sahodaran), funded by NIAID through a Center for AIDS Research (CFAR) supplement to the Harvard CFAR, and approved by ICMR, HMSC, and NACO. Our most recent work was a behavioral sero-prevalence study of MSM in Chennai, including a cross-sectional baseline behavioral assessment and HIV testing with 200 MSM, which lays the groundwork for the trial proposed here. After extensive review from NIAID, ICMR, HMSC, and NACO, this study is nearing completion and informs the content of a prevention intervention. Following guidelines for development of a culturally informed intervention, the next logical step is to further develop and pilot test a behavioral HIV prevention intervention with this population. Background. MSM in India are a highly invisible and stigmatized population. Further, they are at high risk for HIV infection, transmitting HIV to their male sexual partners, and, because of strong societal pressure to marry, may also serve as a bridge population and transmit the virus to their wives. To date, most prevention programs targeting MSM in India involve condom distribution and HIV education, but none to our knowledge have been tested in a randomized controlled trial, and none have attempted to address the important cultural and psychosocial contexts facing this population. Design Overview. The project will follow guidelines for developing and validating behavioral interventions (Rounsaville et al., 2001;NIH PA-06-488) with an emphasis on community input;this will ensure accurate cultural relevance versus simply exporting a U.S. based intervention "as is." Accordingly, the current RFA for an R21 is the perfect next step in our program of research because it will allow us to 1) collect additional necessary formative information to tailor the content of the intervention to ensure its cultural applicability, and 2) conduct a pilot randomized controlled trial. This pilot RCT will have the goal of maximizing feasibility and participant acceptability of the intervention, estimating an effect size for a power analysis, and allowing an informed full-scale trial to follow. Based on our pre-existing qualitative and quantitative research and from Community Advisory Board input, we propose a group intervention that addresses contextual factors and psychosocial difficulties facing MSM in India. In addition to covering topics such as HIV risk reduction and strategies for safer sex, the intervention will target culturally relevant psychosocial issues including pressure to marry and have children, self-esteem (i.e., accepting one's sexual orientation and reducing internalized homophobia), and substance use (i.e., drugs and alcohol).